At the title screen, hold White + Black and press Up, Right, Left, Down. Then, release White + Black and press L + R. All multi-player mode characters will be unlocked, as well as Tesshu in story and co-op modes.

At the item selection screen, hold L + R + White and press Up(2), Down(2), Left, Right, Left, Right. Although you can only still carry six different items, you can have an unlimited amount of those specific items.

At the title screen, hold L + R and press Down, X(2), Up, X(2), Left, X(2), Right, X(2). Alternatively, successfully complete all Rikmaru and Ayame's missions with a "Expert Ninja" rank and Tesshu's missions with a "Professional" rank. Enter the options screen and select "Audio", then "Language". Select the "B-Side" option to play the game with joke and outtake-style dialogue. Note: This is only available in the North American and European version of the game.

Play as Tesshu

Successfully complete the game with Rikimaru and Ayame to unlock Tesshu.

Play as Ninja Dog in multi-player mode

Get a "Grand Master" rank on all of Ayame's missions to unlock Ninja Dog in multi-player mode.

New items

Get a rank of Grand Master on a level to unlock new items. The item is different for every level.

Easy kills around corners

When you have your back against a wall and are peeking around a corner, if there is a guard there, toss a poison rice ball (the one with the green leaf) by pressing Y. As soon as the guard picks it up, run around the corner and Stealth Kill. It does not matter if he is facing you, but try to kill him before he eats it. By doing this you can use the same rice ball on multiple guards.